Drugs Chemicals and Health Course Notes
1/03/13
Introduction to Pharmacology II
Targets of Drug Action
March 5
How do drugs work? | Nearly all drugs act by interfering or inhibiting natural processes which are required for normal physiological function but which may have been disrupted by disease. | Paul Ehrlich 1845-1915 | Observed that certain chemicals or drugs bound in a selective manner to some but not all cells. He recognised that the cells must have chemical recognition sites for these drugs. The concept of a “receptor” was bornOver the last 100 years we have identified the recognition sites for many known drugs This information has been used to: -design new drugs -understand the biological impact of chemicals -Allowed better understanding of physiological function and disease | Regulatory proteins are the targets 1 Carriers/ transporters2 Enzymes 3 Ion channels 4 Receptors The exception: DNA | There are thousands of known targets and many more to be discovered. | Target 1 Carriers | The body has to move nutrients and waste products into and out of cells and organs This function is often carried out by specialised proteins which sit in cell membranesAlso known as a transporter protein The movement of ions and small organic molecules across cell membranes generally occurs either through channels (see above), or through the agency of a transport protein, because the permeating molecules are often too polar (i.e. insufficiently lipid soluble) to penetrate lipid membranes on their own Examples of particular pharmacological importance include those responsible for the transport of ions and many organic molecules across the renal tubule, the intestinal epithelium and the blood-brain barrier, the transport of Na+ and Ca2+ out of cells, and the uptake of neurotransmitter precursors (such as choline) or of neurotransmitters themselves (such as noradrenaline, 5-hydroxytryptamine [5-HT], glutamate and peptides) by nerve terminals, and the transport of drug molecules and their
Introduction to Pharmacology II
Targets of Drug Action
March 5
How do drugs work? | Nearly all drugs act by interfering or inhibiting natural processes which are required for normal physiological function but which may have been disrupted by disease. | Paul Ehrlich 1845-1915 | Observed that certain chemicals or drugs bound in a selective manner to some but not all cells. He recognised that the cells must have chemical recognition sites for these drugs. The concept of a “receptor” was bornOver the last 100 years we have identified the recognition sites for many known drugs This information has been used to: -design new drugs -understand the biological impact of chemicals -Allowed better understanding of physiological function and disease | Regulatory proteins are the targets 1 Carriers/ transporters2 Enzymes 3 Ion channels 4 Receptors The exception: DNA | There are thousands of known targets and many more to be discovered. | Target 1 Carriers | The body has to move nutrients and waste products into and out of cells and organs This function is often carried out by specialised proteins which sit in cell membranesAlso known as a transporter protein The movement of ions and small organic molecules across cell membranes generally occurs either through channels (see above), or through the agency of a transport protein, because the permeating molecules are often too polar (i.e. insufficiently lipid soluble) to penetrate lipid membranes on their own Examples of particular pharmacological importance include those responsible for the transport of ions and many organic molecules across the renal tubule, the intestinal epithelium and the blood-brain barrier, the transport of Na+ and Ca2+ out of cells, and the uptake of neurotransmitter precursors (such as choline) or of neurotransmitters themselves (such as noradrenaline, 5-hydroxytryptamine [5-HT], glutamate and peptides) by nerve terminals, and the transport of drug molecules and their